Why did Modi implement the policy of demonetization of high value currency notes only to recover 6% of black money held in cash at great human loss?

The fact you need to understand is that any one who says any criticism against demonetization is either trying to protect the tax evaders or is against the nation. Hence you should not raise such questions and prevent yourself from being painted as an anti-nationalist.

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In this populist narrative that PM Modi has constructed and strengthened through hundreds of speeches over the years that

• the Congress(opposition as a whole) equals the corrupt equals the black money hoarders equals the elites equals the liberals equals the Modi-critics equals the anti-nationals equals the bad people who want to destroy India.
• At the same time, the good people equals the true nationalists equals Modi equals Modi supporters equals the Congress-haters(oppose opposition).

Neither of these concatenations is fixed — they are liable to be extended to include new categories or shrunk to focus on a select few. Eg: The media who says about the problems of common man.
But as encapsulated in Mr. Modi’s teary-eyed appeal at Goa after demonetization which is a perfect example of this , the significant aspects are three:

1. the moralisation of politics,
2. the infusion of emotion into policy debates, and
3. the reduction of all debate into a single question,

are you in support of Mr. Modi or not?

• If yes, support him.
• If no, then it’s hardly surprising that you are criticising what he has done.

To know more this political strategy read the article The morality of binaries (Hindu Editorial 18/11/2016)
ROLE OF MEDIA IN DEMOCRACY
Media plays a crucial role in shaping a healthy democracy. It is the backbone of a democracy. Media makes us aware of various social, political and economical activities happening around the world. It is like a mirror, which shows us or strives to show us the bare truth and harsh realities of life.
Media shows the different aspects of the same problem. To empathize with the problems common man face is the role of responsible media. It is evident fact that the common man is facing the wrath of demonetization.
Role of media in democracy
CONCLUSION
Hence as a true patriot you should accept and believe the fact that demonetization is good for the nation. It is predicted to adversely affect GDP and it has already lead to unemployment to the low income groups, but still it is a good move. It is quite certain that the ripple effect demonetization created will affect our economy for a while,may be months while some say years. The effect will swallow the gain(if any) we may gain through this whole process . Hence demonetization is good move and we have to appreciate the government for the same.
[Expecting this answer to be deleted or collapsed in a short time, similar to my other answers] :-)